Method for treating a metal melt

Abstract

A method of treating molten metal in a converter having an induction heater the heating space of which opens into the lowermost portion of the converter compartment comprises injecting a mixture of a solid treating material in powder form with a carrier gas through a sidewall of the converter at a level only slightly above the bottom wall of the converter compartment. A tuyere through which the gas-powder mixture is injected is directed slightly downward and toward the region where the heating space of the induction heater opens into the converter compartment.

What is claimed is: 
     
       1. A method for treating a bath of molten metal in a reaction vessel having a refractory lining and at least one induction-heated space opening into the lower portion of the reaction vessel, said method comprising the step of injecting into the bath a mixture of gas and a solid material in powder form, said mixture containing at least 5 kilograms of solid material per cubic meter, as measured at normal temperature and pressure, of gas, and being injected through a tuyere extending through the lining and opening into the bath below the surface thereof, the injection being made in a direction between 15° above and 45° below the horizontal direction and at such a velocity and at such a weight rate that the momentum of the solid material corresponds to an injection of at least 0.03 kilogram of solid material per minute per square millimeter of internal cross-sectional area of the tuyere. 
     
     
       2. A method as claimed in claim 1 in which the mixture of gas and solid material contains at least 15 kilograms of solid material per cubic meter, as measured at normal temperature and pressure, of gas. 
     
     
       3. A method as claimed in claim 1 in which the momentum of the injected solid material corresponds to injection of at least 0.1 kilogram of solid material per minute per square millimeter of internal cross-sectional area of the tuyere. 
     
     
       4. A method as claimed in claim 1 in which the momentum of the injected solid material corresponds to injection of at least 0.3 kilogram of solid material per minute per square millimeter of internal cross-sectional area of the tuyere. 
     
     
       5. A method claimed in claim 1 in which the mixture of gas and solid material is injected in a direction between the horizontal direction and 30° below the horizontal direction. 
     
     
       6. A method as claimed in claim 1 in which the mixture of gas and solid material is injected in a direction between 8° and 22° below the horizontal direction. 
     
     
       7. A method as claimed in claim 1 in which the mixture of gas and solid material is injected through a sidewall of the reaction vessel towards the center of the region in which the heating space opens into the lower portion of the reaction vessel, said injection taking place from a diametrically opposite region of said lower portion.